CM5 Carrier board Community Project?

Creators & Developers Mainboard
1

For a while now, I think about creating a carrier board for a CM5 module.
Now, since it is out and know the specs, we could maybe work towards a way to make it work.
Of course, not everything will work and it won’t be a simple weekend project.

  • Battery
  • Display
  • USB-C / Thunderbolt Ports
  • Audio Jack
  • Speakers
  • Input Cover
    • Finger Printreader
    • Keyboard
    • Trackpad
  • Wi-Fi
  • Bluetooth
  • Camera
  • Microphone
  • RAM (on board of CM5)
  • Storage (via PCIe)

Display

The Raspberry PI supports HDMI, maybe we can turn one of the HDMI signals to eDP using “LT6711” from Lontium Semiconductor.

Input Cover (Fingerprint Reader, Keyboard, Trackpad)

This project turns the whole Input Cover into a USB Device.

Wi-Fi and Bluetooth

Just wire up the antennas the built-in Infineon CYW43455 chip?

Storage

Either built-in eMMC or NVMe via PCIe?

…?

What do you guys think?

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2

Not sure the returns would be worth the effort. What are you getting from the RPI5 that you are not already getting in spades from the current available mainboards?

This is a regression in specs and that seems to be about it. You also won’t get any low power modes, like suspend / standby.

That said, have you heard of MNT? They are taking CM boards from all kinds of ARM manufacturers and putting them into carrier boards for their various product platforms.

Maybe that is something you want, but is already being done?

3

I’m not a gamer.
I know enough people who have a mindset of “why it would not work” instead “what can we do to make it work”. They don’t have joy in creating things, tinkering around and learning new skills.

The idea of Framework is that parts can be replaced by things that they don’t sell and we are here in the creator forum.
Buying a MNT notebook should not be the solution, especially not while Framework exists and we as DIY people are already invested in the eco system.

4

It’s more of a “What would you get if you could make it work” which isn’t all that much here.

For that it’s a perfectly suitable project

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5

Might be worth chatting to FW or Deep computing to see how easy it would be.
I guess a stepping stone might be to duplicate all the USB PD, Battery and EC from a FW main board. That would give you the power on/off and charge functionality.
Then interface the EC to the CM5 and get the CM5 talking USB4 somehow or at least USB3 with DP/HDMI alt mode so it can use the FW Expansion slot cards.
Does the CM5 already have the equivalent of an EC or not?
From a marketing perspective, I don’t know whether there would be any demand for it though.

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6

I really like the idea of this project. I think it could offer a lower cost and more power efficient (maybe) ARM version of the FW13 or even FW16 with far fewer features for those who like to tinker. It would also allow people to upgrade or even “side-grade” to RockChip based boards.
Like Deep Computing’s main board, I don’t think anyone outside the hobby/research community would buy it.

Saying all that, I would jump on this so fast.
Batch 1 CM5 carrier board LETS GOOOOOOO!

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7

Last night in the #framework-discussion channel on Discord, we discussed the dimensions and whether the CM5 module would fit within the Framework case.

What we know:

  • The CM5, including its mating connectors, is 4.94mm thick.
  • There are two connectors for the compute modules (1.5mm and 4.0mm [mated])
  • The thickest part of the Framework mainboard is approx. 6.8mm.
  • A PCB typically measures 1.57mm in thickness.
  • We have to leave approx. 1.1mm clearance below the mainboard, as the standoffs dictate where the PCB can start.
  • We probably would have to rely on the case as a heatsink / no active cooling.

Based on these dimensions:

4.94mm (CM5 + connectors) + 1.57mm (carrier board) = 6.51mm, which is less than the 6.8mm limit of the Framework mainboard.

While this seems promising in theory, the carrier board would need to sit on top of the motherboard standoffs. This would result in a significant offset.

Option A

Instead of connecting the CM5 directly to carrier board, we connect it facing down to another PCB (let’s call it bridge) which then is connected to the carrier board.
For that, we’d need to reduce the PCB thickness to 0.8mm.

Would look like this:

Carrier Board with Bridge (Option A)
Carrier Board with Bridge (Option A)4993×4487 391 KB

And with measurements like this

Option A
Option A3417×1377 167 KB

Option B

If we reduce the thickness of the carrier board to 0.6mm then we could even stack everything on top.

Option B
Option B3417×1316 153 KB

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8

The chip in the pi5 isn’t all that efficient so I doubt it’ll beat the current offerings in pretty much any workload, and that is ignoring what hdmi to edp chipsets and stuff like that would also pull.

Something with an rk3588 may be a better option for that but the software support for that sucks a lot more than anything raspberry and still won’t beat anything else framework has so far in power consumption on anything you’d remotely do on a laptop.

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